From Globes to Maps

Geography Handbook8 / 21 / 2014

From Globes to Maps• The most accurate way to depict the earth is as

a globe, a round scale model of the earth. A globe gives a true picture of the continents’ relative sizes and the shapes of landmasses and bodies of water. Globes accurately represent distance and direction.

•Maps, however, do have their limitations. As you can imagine, drawing a round object on a flat surface is very difficult.

•However, when the curves of a globe become straight lines on a map, the size, shape, distance, or area can change or be distorted.

Common Map Projections• Imagine taking the whole peel from an orange

and trying to flatten it on a table. You would either have to cut it or stretch parts of it. Mapmakers face a similar problem in showing the surface of the round earth on a flat map. When the earth’s surface is flattened, big gaps open up. To fill in the gaps, mapmakers stretch parts of the earth. They choose to show either the correct shapes of places or their correct sizes. It is impossible to show both. As a result, mapmakers have developed different projections, or ways of showing the earth on a flat piece of paper.

Goode’s Interrupted Equal-Area projection. A map with this projection shows continents close to their true shapes and sizes. This projection is helpful to compare land areas among continents.

A map using the Robinson projection has minor distortions. Land on the western and eastern sides of the Robinson map appears much as it does on a globe. The areas most distorted on this projection are near the North and South Poles.

The Winkel Tripel projection gives a good overall view of the continents’ shapes and sizes. Land areas in a Winkel Tripel projection are not as distorted near the Poles as they are in the Robinson projection.

The Mercator projection shows true direction and land shapes fairly accurately, but not size or distance. Areas that are located far from the Equator are quite distorted on this projection.

Types of Maps

• Physical maps show landforms and water features. The colors used on physical maps include brown or green for land, and blue for water. These colors and shadings may show relief—or how flat or rugged the land surface is.

• Political maps show the names and boundaries of countries, the location of cities and other human-made features of a place, and often identify major physical features. It also shows cities and rivers.

• One kind of physical map, called a contour map, also shows elevation